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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Axiomatic choice under uncertainty: a history of von Neumann and Morgenster\'s theory of games / Escolha sob incerteza axiomática: uma história do theory of games de Von Neumann e Morgenstern

Graciani, Marcos Thiago 17 June 2019 (has links)
This dissertation studies the immediate reception of von Neumann and Morgenstern\'s Theory of Games and Economic Behavior. It focuses on how economists (and other scientists, such as mathematicians) reacted to von Neumann and Morgenstern\'s axiomatization of expected utility theory. Such study employs book reviews the Theory of Games received, articles authored by mathematically-proficient readers who followed von Neumann and Morgenstern\'s lead of axiomatizing choice under uncertainty, and articles that cited the later. The main conclusions are threefold. First, to understand the history of the Theory of Games\' reception it is unavoidable to consider how secondary sources acted as disseminators of its premises, results, and method. Second, many skilled authors reflected on von Neumann and Morgenstern\'s book. Most economists who used that literature in an axiomatic framework cited such contributions to borrow and adapt assumptions. Those who applied results directly generally used less-sophisticated mathematical tools and were not proof-driven. Third, while the independence axiom is a necessary condition for expected utility theory, economists struggled to understand how von Neumann and Morgenstern used it. It was not clear where the Theory of Games hid that assumption. After economists discovered the independence axiom, they did not find an immediate use for it / Esta dissertação estuda a recepção imediata do Theory of Games and Economic Behavior, de von Neumann e Morgenstern. Seu foco reside em como economistas (e outros cientistas, tais como matemáticos) reagiram à axiomatização da teoria de utilidade esperada composta por von Neumann e Morgenstern. Tal estudo se vale de resenhas do Theory of Games, artigos autorados por leitores proficientes em matemática que seguiram a deixa dos autores de axiomatizar teoria de escolha sob incerteza e, por fim, artigos cujas citações incluem trabalhos destes leitores habilidosos. Há três conclusões principais. Primeiro, para entender a história de recepção do Theory of Games, é importante considerar que fontes secundárias agiram como disseminadores de premissas, resultados e o próprio método do Theory of Games. Segundo, muitos leitores capazes refletiram sobre o livro de von Neumann e Morgenstern. A maioria dos que usaram tal literatura a fizeram de acordo com o método axiomático, citanto aqueles artigos para reproduzir ou adaptar hipóteses. Dentre os que os citaram para aplicar seus resultados diretamente usaram ferramentas matemáticas menos sofisticadas e não tinham como objetivo a produção de demonstrações formais, em geral. Terceiro, enquanto o axioma de independência é uma condição necessária para a teoria de utilidade esperada, economistas tiveram dificuldades em compreender como von Neumann e Morgenstern usaram-no. Não estava claro para eles onde o Theory of Games o havia escondido. Uma vez que os economistas descobriram o axioma, não encontraram uso imediato para ele
12

Modelos de sobrevivência bivariados baseados na cópula FGM : uma abordagem bayesiana

Suzuki, Adriano Kamimura 07 February 2012 (has links)
Made available in DSpace on 2016-06-02T20:04:51Z (GMT). No. of bitstreams: 1 4292.pdf: 1258858 bytes, checksum: c7d8d771d500d5ab8d54fbaae144001b (MD5) Previous issue date: 2012-02-07 / Financiadora de Estudos e Projetos / In this work we present a Bayesian analysis for bivariate survival data in the presence of a covariate and censored observations. We propose a bivariate distribution for the bivariate survival times based on the Farlie-Gumbel-Morgenstern (FGM) copula to model data with weak dependence. Some survival models with and without cure rate have been assumed for the marginal distributions. For inferential purpose a Bayesian approach via Markov Chain Monte Carlo (MCMC) was considered. Further, some discussions on model selection criteria are given and comparisons with other copula models were performed. To detect influential observations in the data we consider a Bayesian case deletion influence diagnostics based on the -divergence. The OpenBUGS and R systems were used to simulate samples of the posterior distribution. Numerical illustrations are presented considering artificial and real data sets. / Neste trabalho apresentamos uma análise bayesiana para dados de sobrevivência bivariados na presença de covariáveis e observações censuradas. Propomos uma distribuição bivariada para os tempos de sobrevivência baseada na cópula de Farlie- Gumbel-Morgenstern (FGM) para modelar dados com fraca dependência. Alguns modelos de sobrevivência com e sem fração de cura foram assumidos para as distribuições marginais. Para fins inferenciais foi considerada uma abordagem bayesiana usando métodos Monte Carlo em Cadeias de Markov (MCMC). Além disso, algumas discussões sobre os critérios de seleção de modelos são apresentadas e comparações com outras cópulas foram realizadas. A fim de detectar observações influentes nos dados analisados foi utilizado o método bayesiano de análise de influência caso a caso baseado na divergência. Os sistemas OpenBUGS e R foram utilizados para simular amostras da distribuição a posteriori de interesse. Ilustrações numéricas são apresentadas considerando conjunto de dados artificiais e reais.
13

Análise de estabilidade de taludes pelos métodos de Morgenstern-Price e Correia

Freitas, Marco António Coelho January 2011 (has links)
Tese de mestrado integrado. Engenharia Civil (Geotecnia). Universidade do Porto. Faculdade de Engenharia. 2011
14

Os métodos de equilíbrio limite e dos elementos finitos na análise de estabilidade de taludes

Silva, João Paulo Moreira da January 2011 (has links)
Tese de mestrado integrado. Engenharia Civil. Faculdade de Engenharia. Universidade do Porto. 2011
15

The cybernetics of nonzero sum games : the prisoner's dilemma reinterpreted as a pure conflict game with nature, with empirical applications

Bell, Robert I. January 1972 (has links)
In this thesis a new solution concept is developed for n-player, nonzero sum games. The solution concept is based in reinterpreting the n-player nonzero sum game into 2-player zero sum games. The n-player nonzero sum game is first rewritten as an n + 1 player coalition game. The definition of zero sum payment is that one player pays the other what he gets in a given outcome (coalition of the n + 1 player game). Who pays whom depends on the coalition. More than one 2-player zero sum interpretation game always results from the procedure, and criteria are established to select one of the zero sum interpretation games. The solution concept defines results identical to the minimax concept when applied directly to zero sum 2-player games. When applied to 2-player prisoner’s dilemma games, the solution procedure assigns mixed strategies to the prisoners, thereby “resolving” the dilemma. The mixed strategies vary with the payoffs (up to a linear transformation). For prisoner’s dilemma matrices which have been used in large numbers of gaming experiments, the solution concept predicts dynamically, i.e., by play number, the “fraction of cooperative choices” for (approximately) the first 30 plays. In addition, the mixed strategy appears in a game between each subject (prisoner) and the n + 1st player (district attorney), suggesting that the subjects have been playing against the experimenter. Empirical evidence for this conclusion is given. A theorem is proved for n-player prisoner’s dilemma games. Game theory is reviewed to show the roots of this solution concept in the heuristic use of zero sum n-player games in the von Neumann and Morgenstern theory, and in rational decision making models, e.g., “games against Nature.” The empirical and formal difficulties of the equilibrium point solution concept for nonzero sum games are discussed. Detailed connections between game theory and cybernetics are discussed.
16

An Interpretive and Compositional Analysis of the Songs of Yrjö Kilpinen to Poems by Christian Morgenstern

Foster, Walter Charles 06 1900 (has links)
This study examines the the songs of Yrjö Kilpinen and their use in the poems of Christian Morgenstern.
17

Josef Hiršal - monografická studie / Josef Hiršal - monographical study

Marková, Lucie January 2011 (has links)
This monographical work describes the life and work of the poet and translator Josef Hiršal in a chronological way. It is a reason why the work has two main part A, B. The first part A. Life and work of Josef Hiršal maps the importatnt bibliography moments, which had main influent on forming Hiršal's personality and work. Part two B. Bibliography of Josef Hiršal contains multi-layered bibliography of Josef Hiršal. This part try to catch and segment in a several sections Hiršal's literary produciton in all area.
18

Oskar Morgenstern als wirtschaftspolitischer Berater in den 1930er-Jahren

Klausinger, Hansjörg January 2006 (has links) (PDF)
The point of departure of this study is that in the 1930s Oskar Morgenstern, well-known as the co-founder of game theory, was preoccupied by his activities in Austrian economic policy, possibly even more so than with his project to revolutionize economic theory. The main questions to be examined in this regard are, first, to what extent Morgenstern's advice did conform to the teachings of the Austrian school and, second, if he really exerted an influence on economic policy-making in Austria during this period. In order to answer this question the paper draws to a large part on unpublished sources from the Oskar Morgenstern Papers and uses them as a basis for determining Morgenstern's role in a few critical episodes of Austrian economic policy-making. (author's abstract) / Series: Department of Economics Working Paper Series
19

Risk preferences and their robust representation

Drapeau, Samuel 16 June 2010 (has links)
Ziel dieser Dissertation ist es, den Begriff des Risikos unter den Aspekten seiner Quantifizierung durch robuste Darstellungen zu untersuchen. In einem ersten Teil wird Risiko anhand Kontext-Invarianter Merkmale betrachtet: Diversifizierung und Monotonie. Wir führen die drei Schlüsselkonzepte, Risikoordnung, Risikomaß und Risikoakzeptanzfamilen ein, und studieren deren eins-zu-eins Beziehung. Unser Hauptresultat stellt eine eindeutige duale robuste Darstellung jedes unterhalbstetigen Risikomaßes auf topologischen Vektorräumen her. Wir zeigen auch automatische Stetigkeitsergebnisse und robuste Darstellungen für Risikomaße auf diversen Arten von konvexen Mengen. Diese Herangehensweise lässt bei der Wahl der konvexen Menge viel Spielraum, und erlaubt damit eine Vielfalt von Interpretationen von Risiko: Modellrisiko im Falle von Zufallsvariablen, Verteilungsrisiko im Falle von Lotterien, Abdiskontierungsrisiko im Falle von Konsumströmen... Diverse Beispiele sind dann in diesen verschiedenen Situationen explizit berechnet (Sicherheitsäquivalent, ökonomischer Risikoindex, VaR für Lotterien, "variational preferences"...). Im zweiten Teil, betrachten wir Präferenzordnungen, die möglicherweise zusätzliche Informationen benötigen, um ausgedrückt zu werden. Hierzu führen wir einen axiomatischen Rahmen in Form von bedingten Präferenzordungen ein, die lokal mit der Information kompatibel sind. Dies erlaubt die Konstruktion einer bedingten numerischen Darstellung. Wir erhalten eine bedingte Variante der von Neumann und Morgenstern Darstellung für messbare stochastische Kerne und erweitern dieses Ergebnis zur einer bedingten Version der "variational preferences". Abschließend, klären wir das Zusammenpiel zwischen Modellrisiko und Verteilungsrisiko auf der axiomatischen Ebene. / The goal of this thesis is the conceptual study of risk and its quantification via robust representations. We concentrate in a first part on context invariant features related to this notion: diversification and monotonicity. We introduce and study the general properties of three key concepts, risk order, risk measure and risk acceptance family and their one-to-one relations. Our main result is a uniquely characterized dual robust representation of lower semicontinuous risk orders on topological vector space. We also provide automatic continuity and robust representation results on specific convex sets. This approach allows multiple interpretation of risk depending on the setting: model risk in the case of random variables, distributional risk in the case of lotteries, discounting risk in the case of consumption streams... Various explicit computations in those different settings are then treated (economic index of riskiness, certainty equivalent, VaR on lotteries, variational preferences...). In the second part, we consider preferences which might require additional information in order to be expressed. We provide a mathematical framework for this idea in terms of preorders, called conditional preference orders, which are locally compatible with the available information. This allows us to construct conditional numerical representations of conditional preferences. We obtain a conditional version of the von Neumann and Morgenstern representation for measurable stochastic kernels and extend then to a conditional version of the variational preferences. We finally clarify the interplay between model risk and distributional risk on the axiomatic level.
20

Performance analysis of spectrum sensing techniques for cognitive radio systems

Gismalla Yousif, Ebtihal January 2013 (has links)
Cognitive radio is a technology that aims to maximize the current usage of the licensed frequency spectrum. Cognitive radio aims to provide services for license-exempt users by making use of dynamic spectrum access (DSA) and opportunistic spectrum sharing strategies (OSS). Cognitive radios are defined as intelligent wireless devices capable of adapting their communication parameters in order to operate within underutilized bands while avoiding causing interference to licensed users. An underused band of frequencies in a specific location or time is known as a spectrum hole. Therefore, in order to locate spectrum holes, reliable spectrum sensing algorithms are crucial to facilitate the evolution of cognitive radio networks. Since a large and growing body of literature has mainly focused into the conventional time domain (TD) energy detector, throughout this thesis the problem of spectrum sensing is investigated within the context of a frequency domain (FD) approach. The purpose of this study is to investigate detection based on methods of nonparametric power spectrum estimation. The considered methods are the periodogram, Bartlett's method, Welch overlapped segments averaging (WOSA) and the Multitaper estimator (MTE). Another major motivation is that the MTE is strongly recommended for the application of cognitive radios. This study aims to derive the detector performance measures for each case. Another aim is to investigate and highlight the main differences between the TD and the FD approaches. The performance is addressed for independent and identically distributed (i.i.d.) Rayleigh channels and the general Rician and Nakagami fading channels. For each of the investigated detectors, the analytical models are obtained by studying the characteristics of the Hermitian quadratic form representation of the decision statistic and the matrix of the Hermitian form is identified. The results of the study have revealed the high accuracy of the derived mathematical models. Moreover, it is found that the TD detector differs from the FD detector in a number of aspects. One principal and generalized conclusion is that all the investigated FD methods provide a reduced probability of false alarm when compared with the TD detector. Also, for the case of periodogram, the probability of sensing errors is independent of the length of observations, whereas in time domain the probability of false alarm is increased when the sample size increases. The probability of false alarm is further reduced when diversity reception is employed. Furthermore, compared to the periodogram, both Bartlett method and Welch method provide better performance in terms of lower probability of false alarm but an increased probability of detection for a given probability of false alarm. Also, the performance of both Bartlett's method and WOSA is sensitive to the number of segments, whereas WOSA is also sensitive to the overlapping factor. Finally, the performance of the MTE is dependent on the number of employed discrete prolate spheroidal (Slepian) sequences, and the MTE outperforms the periodogram, Bartlett's method and WOSA, as it provides the minimal probability of false alarm.

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